Process for making flameproofed dyed aminized cotton fabrics



United States Patent PROCESS FOR MAKING FLAMEPROOFED DYED AMENIZEDCOTTON FABRICS Uscar J. McMilian, Jr., and John D. Guthrie, New Orleans,

La, assignors to the United States of America as represented by theSecretaryof Agriculture No Drawing. Application May 9, 1952, Serial No.287,025

4 Claims. (Cl. 8-57) (Granted under Title 35, U. S. Code (1952), see.266) A non-exclusive, irrevocable, royalty-free license in the inventionherein described, for all governmental purposes, throughout the world,with the power to grant sublicenses for such purposes, is hereby grantedto the Government of the United States of America.

This invention relates to reducing the combustibility of materialscomposed essentially of cellulose fibers, particularly cotton fabrics.More particularly this invention provides a process of producing deeplycolored cotton fabrics of low combustibility.

We have discovered that cotton fabrics can be aminized and dyed toproduce deeply colored fabrics of low combustibility. We have furtherdiscovered that such fabrics can be impregnated with poly(triallylphosphate) to produce deeply colored fabrics having a hand and feeladapting them for the conventional uses of deeply colored fabrics,having a marked resistance to changes in flammability due to washing,and having flammability properties enabling them to pass the AmericanAssociation of Textile Chemists and Colorists Standard Test Method 3437Vertical Flame Test.

In general, according to this invention, materials composed of cellulosefibers, preferably cotton fabrics, are converted to deeply coloredfabrics of low combustibility by: aminizing them until they have anamine nitrogen content of at least about 0.6% and dyeing them with anacid reacting azo dye containing at least one radical of the groupconsisting of phosphato and sulfo radicals until at least 7% of theweight of the dyed fabric is dyestuif. Deeply dyed fabrics which willpass the above vertical flame test are produced by: aminizing and dyeingcotton fabrics in the same way; impregnating the dyed fabrics with asolution of poly(triallyl phosphate) until at least poly(triallylphosphate) is dispersed throughout the interstices of the fabric; andremoving the solvent and curing the fabric.

While the cotton fabric can suitably be aminized by a variety of knownmethods, the fabric is preferably aminized by aminoethylation, forexample by the process described in U. S. 2,459,222. While theaminization can suitably be conducted to produce aminized fabricscontaining a substantially greater proportion of amino nitrogen, anaminization to an amino nitrogen content of greater than about 1%markedly increases the boardyness of the fabric.

Substantially any acid reacting azo dye containing at least one radicalof the group consisting of phosphato and sulfo radicals can suitably beused. Preferred dyes include the phosphorous containing dyes describedin U. S. 2,183,998 and the sulfur containing dyes described in thecolour index published by the Society of Dyers and Colourists of GreatBritain. Direct cotton dyes are par ticularly suitable in that their useresults in a particularly high retention of the property of lowflammability after launderings and the like treatments. Particularlysuitable dyes include those commercially available under the tradenames: Kiton Fast Red; Kiton Fast Yellow; Kiton Red S; Kiton Blue A;Kiton Red G; Kiton Red 6B; Kiton Fast Orange G; Kiton Fast Green V;Kiton Fast Violet 10B; Amacid Light Yellow 2G; Amacid Brilliant Orange;National Diazine Black H; Pontamine Fast Blue 4G LN; National ErieYellow F; Pontamine Sky Blue 6BX; Pontamine Fast Pink BL.

While the aminized cotton fabric can suitably be dyed untilsubstantially more than about 7% of the weight of the dyed fabric ispure dye, little advantage is provided by the presence of the additionalamount, and dyeing until about 7% of the weight of the dyed fabric isdyestuif is preferred. in practice, due to the fact that commercial dyesare seldom pure, about 10 percent or more of Eommercial dyes, based onthe weight of the fabric, is use The dyeing can suitably be conducted inaccordance with the"conventiona1 processes of dyeing aminogroupcontaining fabrics. Wool dyes are preferably applied in an acidmedium, and aqueous mediums made acid with acetic acid are particularlysuitable. Direct cotton dyes are preferably applied in an aqueous mediumwhich is initially slightly basic and which is rendered acidic by theaddition of acetic acid. The dyeing is preferably aided by the additionof salt to the aqueous medium containing the dye, toward the end of thedyeing operation.

The poly(triallyl phosphate) used in the process of this invention cansuitably be a liquid polymer or a solid polymer which is appreciablysoluble in some volatile organic solvent. Suitable methods of preparingtriallyl phosphate are described in U. S. 2,394,829. Polymerization isaccomplished by known methods using a peroxide, for example, benzoylperoxide, as a catalyst. While the poly(triallyl phosphate) can suitablybe applied to the dyed aminized fabric in the form of a solution insubstantially any relatively volatile organic solvent for poly(triallylphosphate) a particularly suitable solvent for such use is the methylalcohol-ethylene chloride azeotrope boiling at about 61 C. The solutionof poly(triallyl phosphate) is prefer-ably one which contains from about3 to about 15 percent poly(triallyl phosp ate).

The aminized dyed fabric can suitably be impregnated with amounts ofpoly(triallyl phosphate) substantially greater or less than about 10%.However, the use of substantially less results in a lesser degree offlameproofing and the use of substantially more results in a greaterdegree of stiifness of the fabric.

The poly(triallyl phosphate) impregnated fabric can suitably be cured bythe conventional processes for curing a chemically impregnated cottonfabric, i. e. in general from about to about C. for from about 60 toabout 20 minutes using a longer time with a lower temperature.

The following examples are illustrative of the invention:

Example 1 8 g. of aminized cotton fabric, consisting of 48 x 48 sheetingthat had been aminoethyl-ated according to U. S. Patent 2,459,222 andwhich contained 0.8 percent amino nitrogen, was placed in a dye bathcontaining 4 g. of Kiton Fast Red dissolved in 1 percent acetic acid.After boiling the fabric in this dye bath for about 30 minutes, thefabric was air dried. It was a very dark shade of red, and at leastabout 10% of its weight was the dyestuff employed.

When a 1 cm. strip of the fabric was held at an angle of from thevertical and lighted at the lower end, the fabric strip did not supportcombustion. The undyed aminized fabric burned completely when lighted inthis position and also burned completely when the strip was held withthe edge at an angle of 45 from the vertical and lighted at the uppercorner.

Example 2 2 g. of a similar aminized cotton fabric containing 0.8percent nitrogen was placed in a dye bath composed of 0.25 g. of KitonRed 6B (sodium salt of p-acetylaminobenzene azo 8 acetylamino 1 naphthol3:6 disulphonic acid), 500 ml. of water and 5 ml. of acetic acid andboiled for 1 hour. The fabric was removed from the bath and air dried.It was a dark shade of red and at least about 10% of its weight was thedyestuff employed.

The flame-resistance of the dyed fabric was similar to {hat ilescribedfor the fabric dyed according to Example Example 3 5 g. of a similaraminized cotton fabric containing 0.8 percent nitgrogen was placed in adye bath composed of 1 g. National Diazine Black H (sodium salt ofdiphenyldisazo 3 sulpho 7 amino 1 naphthol 8aminol-naphthol-3:6-disulphonic acid), 1 g. sodium carbonate and 500 ml.water. After boiling for 30 min., 2 ml. of acetic acid was added, andthe boiling continued for 30 min. more. The fabric was then washed indilute acetic acid solution and air dried. It was a dark shade of blackand at least about 10% of its weight was the dyestuff used.

The dyed fabric did not support combustion when lighted in the 135position as described in Example No. 1.

Example 4 53 g. of a similar aminized fabric containing 0.8 percentnitrogen was dyed in a bath composed of 7 g. of Pontamine Fast Pink BLconc. 125% (sodium salt of 3:3 disulphodiphenyl urea 4:4 disazo bis 2-amino-S-naphthol-6-sulphonic acid), 7 g. of NazCOz and 1500 ml. ofdistilled water at the boil for 30 min. Glacial acetic acid, 10 ml., wasthen added dropwise and the boiling continued for 30 min. followed bythe addition of 20 g. Na2SO4 and 30 min. more boiling.

After thorough washing in water and air drying the dyed fabric was avery dark red, contained about 8% of the pure dyestuff based on sulfuranalysis of the fabric, and showed some flame-resistance, failing tosupport combustion when a strip was held at an angle of 90 from thevertical and lighted at the end.

A 3.8 percent solution of polymerized triallyl phosphate in 68% ethylenechloride and 32% methanol was applied to both sides of the fabric,allowing partial drying between each application. After air drying thefabric was baked for 1 hr. at 100 C. The fabric was thus impregnatedwith about 15% of the polymer.

The fabric was washed twice in a beaker with 0.1% Igepon T solution at60 C. for minutes for each wash, followed by two 5 minute washes in topwater at 60 C.

This was followed by a fluoride laundry sour after which the fabric waswashed thoroughly in water and air dried. The polymer-impregnated dyedfabric did not support combustion when a strip was held in a verticalposition and lighted from the bottom. There was no afterglow. It passedthe vertical flame test of the American Association of Textile Chemistsand Colorists, Standard Test Methtod 34-37. In this test the char lengthwas 3.75 inches and the fabric weight was 7 oz. per square yard. Thefabric contained by analysis 1.08% nitrogen, 2.14% phosphorus and 0.93%sulfur. The dyed fabric prior to application of the polymerized triallylphosphate contained 1.39% nitrogen, 1.13% sulfur and no phosphorus.

We claim:

1. A process of producing a deeply dyed cotton fabric of relatively lowcombustibility, which comprises, aminoethylating the fabric to an aminonitrogen content of at least about 0.6% and dyeing the aminized fabricwith an acid reacting azo dye containing at least one radical of thegroup consisting of phosphato and sulfo radicals until at least about 7%of the weight of the resulting dyed aminized fabric is dyestuif.

2. The process of claim 1 in which the dye is a sodium salt ofp-acetylarnino benzene-azo-8-acetylamino-l-naphthol-3 :6-disu1phonicacid.

3. The process of claim 1 in which the dye is a sodium salt ofdiphenyl-disazo 3 sulpho-7-amino-l-naphthol-8- amino-1-naphthol-36-disulphonic acid.

4. The process of claim 1 in which the dye is a sodium salt of 3 :3'-disulphodiphenyl-urea-4 4'-disazo-bis-2-amino-8-naphthol-6-sulphonicacid.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,330,251 Taylor Sept. 28, 1943 2,459,222 Guthrie Jan. 18,1949

1. A PROCESS OF PRODUCING A DEEPLY DYED COTTON FABRIC OF RELATIVELY LOWCOMBUSTIBILITY, WHICH COMPRISES, AMINOETHYLATING THE FABRIC TO AN AMINONITROGEN CONTENT OF AT LEAST ABOUT 0.6% AND DYEING THE AMINIZED FABRICWITH AN ACID REACTING AZO DYE CONTAINING AT LEAST ONE RADICAL OF THEGROUP CONSISTING OF PHOSPHATO AND SULFO RADICALS UNTIL AT LEAST ABOUT 7%OF THE WEIGHT OF THE RESULTING DYED AMINIZED FABRIC IS DYESTUFF.